kara joined, paula left, ellen arrived, now simon, ellen, and kara are gone. the last man standing? randy jackson. >> i'm going to honestly, honestly miss you. it's been a blast. thank you. >> reporter: the big question, can "idol" ever again find the right mix? especially after losing their sharp-tongued standout. simon cowell is launching his own show on fox. >> without simon it's like "the ellen show" without ellen. it's weird. it will limp along. hopefully, it will find new chemistry that will make it relevant for the next generation. >> reporter: whatever they decide, they better do it soon. callbacks start in a couple of weeks. for "good morning america," jeremy hubbard, abc news, new york. >> and if they want steven tyler, they have to lay out the bread. >> and j. lo. elton john. steven perry. a lot of star power there. >> like weekend "gma." another horrific acid attack leaves a woman severely burned. was it a copycat crime? we'll talk to an expert.